2,488 research outputs found

    The satellite distribution of M31

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    (Abridged) The spatial distribution of the Galactic satellite system plays an important role in Galactic dynamics and cosmology, where its successful reproduction is a key test of simulations of galaxy halo formation. Here, we examine its representative nature by conducting an analysis of the 3-dimensional spatial distribution of the M31 subgroup of galaxies. We begin by a discussion of distance estimates and incompleteness concerns, before revisiting the question of membership of the M31 subgroup. Comparison of the distribution of M31 and Galactic satellites relative to the galactic disks suggests that the Galactic system is probably modestly incomplete at low latitudes by ~20%. We find that the radial distribution of satellites around M31 is more extended than the Galactic subgroup; 50% of the Galactic satellites are found within ~100kpc of the Galaxy, compared to ~200kpc for M31. We search for ``ghostly streams'' of satellites around M31, in the same way others have done for the Galaxy, and find several. The lack of M31-centric kinematic data, however, means we are unable to probe whether these streams represent real physical associations. Finally, we find that the M31 satellites are asymmetrically distributed with respect to our line-of-sight to this object, so that the majority of its satellites are on its near side with respect to our line-of-sight. We quantify this result and find it to be significant at the ~3 sigma level. Until such time as a satisfactory explanation for this finding is presented, our results warn against treating the M31 subgroup as complete, unbiased and relaxed.Comment: 15 pages, 9 figures. Accepted for publication in MNRA

    A community-based group-guided self-help intervention for low mood and stress: study protocol for a randomized controlled trial

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    <br>Background: Depression is a mental health condition which affects millions of people each year, with worldwide rates increasing. Cognitive behavioral therapy (CBT) is recommended in the National Institute for Health and Clinical Excellence (NICE) guidelines for the treatment of depression. However, waiting lists can cause delays for face-to-face therapy. Also a proportion of people decline to present for help through the health service – the so-called treatment gap. Self-referral to CBT using community-based group interventions delivered by a voluntary sector organization may serve to resolve this problem. The aim of this randomized controlled trial (RCT) is to determine the efficacy of such a guided CBT self-help course, the ‘Living Life to the Full’ (LLTTF) classes delivered by the charity Action on Depression (AOD). The primary outcome is level of depression at 6 months assessed using the patient health questionnaire-9 (PHQ9) depression scale. Secondary measures include levels of anxiety and social functioning.</br> <br>Methods/design: Participants with symptoms of low mood will be recruited from the community through newspaper adverts and also via the AOD website. Participants will receive either immediate or delayed access to guided CBT self-help classes - the eight session LLTTF course. The primary endpoint will be at 6 months at which point the delayed group will be offered the intervention. Levels of depression, anxiety and social functioning will be assessed and an economic analysis will be carried out.</br> <br>Discussion: This RCT will test whether the LLTTF intervention is effective and/or cost-effective. If the LLTTF community-based classes are found to be cost effective, they may be helpful as both an intervention for those already seeking care in the health service, as well as those seeking help outside that setting, widening access to psychological therapy.</br&gt

    Language delay is not predictable from available risk factors

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    Aims. To investigate factors associated with language delay in a cohort of 30-month-old children and determine if identification of language delay requires active contact with families. Methods. Data were collected at a pilot universal 30-month health contact. Health visitors used a simple two-item language screen. Data were obtained for 315 children; language delay was found in 33. The predictive capacity of 13 variables which could realistically be known before the 30-month contact was analysed. Results. Seven variables were significantly associated with language delay in univariate analysis, but in logistic regression only five of these variables remained significant. Conclusion. The presence of one or more risk factors had a sensitivity of 89% and specificity of 45%, but a positive predictive value of only 15%. The presence of one or more of these risk factors thus can not reliably be used to identify language delayed children, nor is it possible to define an “at risk” population because male gender was the only significant demographic factor and it had an unacceptably low specificity (52.5%). It is not possible to predict which children will have language delay at 30 months. Identification of this important ESSENCE disorder requires direct clinical contact with all families

    Multiple dynamical components in Local Group dwarf spheroidals

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    The dwarf spheroidal (dSph) satellites of the Local Group have long been thought to be simple spheroids of stars embedded within extended dark matter halos. Recently, however, evidence for the presence of spatially and kinematically distinct stellar populations has been accumulating. Here, we examine the influence of such components on dynamical models of dwarf galaxies embedded in cold dark matter halos. We begin by constructing a model of Andromeda II, a dSph satellite of M31 which shows evidence for spatially distinct stellar components. We find that the two-component model predicts an overall velocity dispersion profile that remains approximately constant at 1011\sim 10 - 11 km s1^{-1} out to 1\sim 1 kpc from the center; this is despite wide kinematic and spatial differences between the two individual components. The presence of two components may also help to explain oddities in the velocity dispersion profiles of other dSphs; we show that velocity dispersion profiles which appear to rise from the center outwards before leveling off--such as those of Leo I, Draco, and Fornax--can result from the gradual transition from a dynamically cold, concentrated component to a second, hotter, and more spatially extended one, both in equilibrium within the same dark halo. Dwarf galaxies with two stellar components generally have a leptokurtic line-of-sight velocity distribution which is well described by a double Maxwellian. Interestingly, we find that multiple equilibrium components could also provide a potential alternative origin for ``extra-tidal'' stars (normally ascribed to tidal effects) in situations where corroborating evidence for tides may be lacking.Comment: Accepted by MNRAS Letters. Revised version, with addition of new section and expanded discussio

    A cluster randomised controlled trial of a pharmacist-led collaborative intervention to improve statin prescribing and attainment of cholesterol targets in primary care

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    Background: Small trials with short term follow up suggest pharmacists’ interventions targeted at healthcare professionals can improve prescribing. In comparison with clinical guidance, contemporary statin prescribing is sub-optimal and achievement of cholesterol targets falls short of accepted standards, for patients with atherosclerotic vascular disease who are at highest absolute risk and who stand to obtain greatest benefit. We hypothesised that a pharmacist-led complex intervention delivered to doctors and nurses in primary care, would improve statin prescribing and achievement of cholesterol targets for incident and prevalent patients with vascular disease, beyond one year.<p></p> Methods: We allocated general practices to a 12-month Statin Outreach Support (SOS) intervention or usual care. SOS was delivered by one of 11 pharmacists who had received additional training. SOS comprised academic detailing and practical support to identify patients with vascular disease who were not prescribed a statin at optimal dose or did not have cholesterol at target, followed by individualised recommendations for changes to management. The primary outcome was the proportion of patients achieving cholesterol targets. Secondary outcomes were: the proportion of patients prescribed simvastatin 40 mg with target cholesterol achieved; cholesterol levels; prescribing of simvastatin 40 mg; prescribing of any statin and the proportion of patients with cholesterol tested. Outcomes were assessed after an average of 1.7 years (range 1.4–2.2 years), and practice level simvastatin 40 mg prescribing was assessed after 10 years.<p></p> Findings: We randomised 31 practices (72 General Practitioners (GPs), 40 nurses). Prior to randomisation a subset of eligible patients were identified to characterise practices; 40% had cholesterol levels below the target threshold. Improvements in data collection procedures allowed identification of all eligible patients (n = 7586) at follow up. Patients in practices allocated to SOS were significantly more likely to have cholesterol at target (69.5% vs 63.5%; OR 1.11, CI 1.00–1.23; p = 0.043) as a result of improved simvastatin prescribing. Subgroup analysis showed the primary outcome was achieved by prevalent but not incident patients. Statistically significant improvements occurred in all secondary outcomes for prevalent patients and all but one secondary outcome (the proportion of patients with cholesterol tested) for incident patients. SOS practices prescribed more simvastatin 40 mg than usual care practices, up to 10 years later.<p></p> Interpretation: Through a combination of educational and organisational support, a general practice based pharmacist led collaborative intervention can improve statin prescribing and achievement of cholesterol targets in a high-risk primary care based population

    Camps of Containment: A Genealogy of the Refugee Camp

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    What is a refugee camp? Existing definitions have focused on logics of power and institutions of governance. This article argues instead that refugee camps are best understood in relation to their purpose of containment. It posits ‘camps of containment’ as a specific form of encampment consisting of three primary categories: prisoner-of-war camps, internment camps and camps for forced migrants. This genealogy sheds new light on the origin of the refugee camp and reveals camps of containment to be an evolving politico-military strategy related to changing patterns of political conflict and to shifting anxieties about national security

    Indigenous and traditional musics in the school classroom : a re-evaluation of the South African Indigenous African Music (IAM) curriculum

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    Musical ideals set by European standards and values, entrenched through colonial oppression and promoted by the continued veneration of Western culture need to be re-evaluated. Despite the intention of the ANC government, through the Department of Basic Education's Curriculum and Assessment Policy Statement music curricula, to integrate Indigenous Knowledge and musics into the South African classroom, evidence shows that opportunities to do so are not seized. With reference to the proclaimed values of an African sensibility in the model of the South African music education curriculum, the history of its development and the current pedagogical movement towards transformation in the production of knowledge and the inclusion of Indigenous Knowledge (IK), this thesis questions why teachers in government schools in South Africa are not executing the Indigenous African Music (IAM) syllabus in the CAPS FET music curriculum. Taking the history of music education and the development of curriculum models and frameworks into account, it interrogates what strategies could improve the application of the current music curriculum in government schools in South Africa. These questions are addressed in the thesis by way of a discussion of the music curriculum and what its praxis in the classroom reveals about its efficacy, through observations and personal experiences, the observations of teachers and student teachers, a comparison with the experience in Zimbabwe, and an analysis of the music curriculum as it is currently devised and implemented. Straddling three methodological approaches, namely the ethnographic, the autoethnographic and the action research approach this study finds that the CAPS FET music curriculum does provide realistic opportunities to engage with African Indigenous and traditional music. This, however, is dependent upon the training of the teacher, facilities available in the classroom and the prior knowledge of the learner. A fundamental flaw of this curriculum is the approach to practical assessment of Indigenous and traditional African musics and the lack of assessment criteria and practical guidelines. In addition, the findings suggest that the fault regarding implementation of the curriculum lies in the training of students (who become teachers) at tertiary level, where an integrated approach to skills development regarding Indigenous African music is suggested

    The Orbital Ellipticity of Satellite Galaxies and the Mass of the Milky Way

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    We use simulations of Milky Way-sized dark matter haloes from the Aquarius Project to investigate the orbits of substructure haloes likely, according to a semi-analytic galaxy formation model, to host luminous satellites. These tend to populate the most massive subhaloes and are on more radial orbits than the majority of subhaloes found within the halo virial radius. One reason for this (mild) kinematic bias is that many low-mass subhaloes have apocentres that exceed the virial radius of the main host; they are thus excluded from subhalo samples identified within the virial boundary, reducing the number of subhalos on radial orbits. Two other factors contributing to the difference in orbital shape between dark and luminous subhaloes are their dynamical evolution after infall, which affects more markedly low-mass (dark) subhaloes, and a weak dependence of ellipticity on the redshift of first infall. The ellipticity distribution of luminous satellites exhibits little halo-to-halo scatter and it may therefore be compared fruitfully with that of Milky Way satellites. Since the latter depends sensitively on the total mass of the Milky Way we can use the predicted distribution of satellite ellipticities to place constraints on this important parameter. Using the latest estimates of position and velocity of dwarfs compiled from the literature, we find that the most likely Milky Way mass lies in the range 6×1011M<M200<3.1×1012M6 \times 10^{11} M_{\odot} < M_{200} < 3.1 \times 10^{12} M_{\odot}, with a best fit value of M200=1.1×1012MM_{200} = 1.1 \times 10^{12} M_{\odot}. This value is consistent with Milky Way mass estimates based on dynamical tracers or the timing argument.Comment: 10 pages, 9 figures, Accepted by MNRA
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